

public class Main1093 {
    public static void main(String[] args) {
            int c=0;
        for (char i = 'a'; i <='z'; i++) {
            System.out.print(i);
            c++;
            if (c % 13 == 0) System.out.print('\n');
        }
        c=0;
        for (char i = 'z'; i >='a'; i--) {
            System.out.print(i);
            c++;
            if (c % 13 == 0) System.out.print('\n');
        }
    }
}
